Converting Municipal Waste into Automobile Fuel: Ethanol from NewspaperMark Mascal and Richard ScownIn this experiment, waste newspaper is pulped with acid and its cellulose hydrolyzed to produce glucose syrup that is fermented and distilled to yield ethanol. In doing so, students are introduced to carbohydrate chemistry and the use of fermentation in organic synthesis.Mascal, Mark; Scown, Richard. J. Chem. Educ.2008, 85, 546.

Chemical Speciation and Calculation of pH of a Sport DrinkJosé L. Guiñón SeguraA recently published laboratory procedure allows students to see that the pointer function has a minimum value at the solution pH. However, the resolution of the pointer function requires the plotting the logarithmic concentration diagram, which is time-consuming and tedious.Segura, José L Guiñón. J. Chem. Educ.2008, 85, 371.

Acids / Bases |

Aqueous Solution Chemistry |

Consumer Chemistry |

Food Science |

Mathematics / Symbolic Mathematics |

pH |

Quantitative Analysis

Acylation of Ferrocene: A Greener ApproachKurt R. Birdwhistell, Andy Nguyen, Eric J. Ramos, and Robert KobeljaThis article describes an acylation of ferrocene that is more eco-friendly than the conventional experiment, which has been modified by replacing mineral acid with a polymeric acid catalyst and using microwave instead of conventional heating.Birdwhistell, Kurt R.; Nguyen, Andy; Ramos, Eric J.; Kobelja, Robert. J. Chem. Educ.2008, 85, 261.

Catalysis |

Chromatography |

Green Chemistry |

Organometallics |

Synthesis |

Transition Elements |

Brønsted-Lowry Acids / Bases

The Role of Water Chemistry in Marine Aquarium Design: A Model System for a General Chemistry ClassJeffrey J. Keaffaber, Ramiro Palma, and Kathryn R. WilliamsWater chemistry is central to aquarium design, and it provides many potential applications for discussion in undergraduate chemistry and engineering courses. This article uses a hypothetical tank to house ocean sunfish as a model to show students the calculations and other considerations that are needed when designing a marine aquarium.Keaffaber, Jeffrey J.; Palma, Ramiro; Williams, Kathryn R. J. Chem. Educ.2008, 85, 225.

Acids / Bases |

Aqueous Solution Chemistry |

Consumer Chemistry |

Oxidation / Reduction |

Stoichiometry |

Water / Water Chemistry

The Chemistry of Paper PreservationHenry A. CarterThis article examines the applications of chemistry to paper preservation. The acid-catalyzed hydrolysis of cellulose accounts for the deterioration of paper in library books and other written records. To combat this threat to our written heritage, new permanent papers have been developed that are relatively chemically stable and undergo a very slow rate of deterioration. Carter, Henry A. J. Chem. Educ.2007, 84, 1937.

Peer-Developed and Peer-Led Labs in General ChemistryLorena Tribe and Kim KostkaDescribes a student-developed and led laboratory curriculum as a model for producing a more student-centered and rich laboratory experience in general chemistry laboratories.Tribe, Lorena; Kostka, Kim. J. Chem. Educ.2007, 84, 1031.

Acids / Bases |

Electrochemistry |

Equilibrium |

Kinetics |

Laboratory Management |

Thermodynamics |

Student-Centered Learning

Oxidation of Aromatic Aldehydes Using OxoneRajani Gandhari, Padma P. Maddukuri, and Thottumkara K. VinodDescribes an eco-friendly procedure for the oxidation of aldehydes to carboxylic acids in water or a water-ethanol mixture using Oxone as the oxidant. The use of eco-friendly solvents, a non-toxic reagent, and the elimination of extraction solvents in the procedure demonstrate important green chemistry themes to students.Gandhari, Rajani; Maddukuri, Padma P.; Vinod, Thottumkara K. J. Chem. Educ.2007, 84, 852.

Aldehydes / Ketones |

Aromatic Compounds |

Aqueous Solution Chemistry |

Carboxylic Acids |

Green Chemistry |

Mechanisms of Reactions |

NMR Spectroscopy |

Oxidation / Reduction

More Thoughts on the Narra Tree FluorescenceA. Ulises AcuñaThe source of L. nephriticum and the substance responsible for the intense blue fluorescence in an earlier published demonstration may require further consideration.Acuña, A. Ulises. J. Chem. Educ.2007, 84, 231.

Titration of a Solid Acid Monitored By X-Ray DiffractionKeenan E. Dungey and Paul EpsteinPresents a solid-state laboratory in which students react fixed amounts of zirconium phosphate with increasing equivalents of NaOH(aq). From X-ray diffraction patterns, students calculate the interplanar spacings before and after the reaction. The spacings increase until the molar equivalence point is reached, indicating incorporation of the sodium ion into the crystal.Dungey, Keenan E.; Epstein, Paul. J. Chem. Educ.2007, 84, 122.

Acids / Bases |

Crystals / Crystallography |

Materials Science |

Solid State Chemistry |

X-ray Crystallography |

Titration / Volumetric Analysis

Chemical Aspects of General Anesthesia: Part I. From Ether to HalothaneRobert Brunsvold and Daryl L. OstercampSummarizes general anesthesia from 1846 to 1956. Events leading up to the adoption of a "balanced" approach, where a sequence of individual compounds is used rather than a single agent, are described.Brunsvold, Robert; Ostercamp, Daryl L. J. Chem. Educ.2006, 83, 1821.

Acids / Bases |

Bioorganic Chemistry |

Chirality / Optical Activity |

Drugs / Pharmaceuticals |

Medicinal Chemistry |

Synthesis

Chemical Aspects of Local and Regional AnesthesiaRobert Brunsvold and Daryl L. OstercampThe chemistry that underlies the development of local and regional anesthesia is explored. Emphasis is placed upon the importance of acidity constants and lipophilic versus hydrophilic character in interpreting what affect a particular compound has upon biological processes.Brunsvold, Robert; Ostercamp, Daryl L. J. Chem. Educ.2006, 83, 1816.

Developing Critical Thinking Skills: The "Sabotaged" Synthesis of Methyl p-BromobenzoateEric J. Mahan and Mary Alice NadingBefore beginning an experiment, students are told that someone might have sabotaged their experiment to produce other-than-expected results. The objective is to perform the experiment, determine if any sabotage has occurred, and, if so, identify the changes that were made to the reagents as well as the person responsible.Mahan, Eric J.; Nading, Mary Alice. J. Chem. Educ.2006, 83, 1652.

Alcohols |

Carboxylic Acids |

Esters |

IR Spectroscopy |

NMR Spectroscopy |

Mass Spectrometry |

Synthesis

Astrochemistry Examples in the ClassroomReggie L. HudsonIn this article some recent developments in astrochemistry are suggested as examples for the teaching of acid-base chemistry, molecular structure, and chemical reactivity. Suggestions for additional reading are provided, with an emphasis on readily-accessible materials.Hudson, Reggie L. J. Chem. Educ.2006, 83, 1611.

pH Paradoxes: Demonstrating That It Is Not True That pH ≡ -log[H+]Christopher G. McCarty and Ed VitzSix demonstrations highlighting paradoxes that arise if pH is incorrectly defined as -log[H+] are presented as justification for the recommendation that pH should be correctly defined as pH = -log aH+ in textbooks.McCarty, Christopher G.; Vitz, Ed. J. Chem. Educ.2006, 83, 752.

Acids / Bases |

Aqueous Solution Chemistry |

Ion Selective Electrodes |

pH |

Quantitative Analysis

Ozonolysis Problems That Promote Student ReasoningRay A. Gross Jr.The structural features inherent in acyclic monoterpenes that follow the isoprene rule often lead to unique sets of ozonolysis products from which their structures, excluding stereochemistry, can be determined from molecular formulas only. This article shows how students may elucidate the structures of these compounds by analysis of the oxidative and reductive workup products.Gross, Ray A., Jr. J. Chem. Educ.2006, 83, 604.

Synthesis of Methyl Diantilis, a Commercially Important FragranceWilliam H. Miles and Katelyn B. ConnellDescribes the synthesis of a family of fragrances, including the commercially important Methyl Diantilis, and provides an excellent introduction to intellectual property laws. Miles, William H.; Connell, Katelyn B. J. Chem. Educ.2006, 83, 285.

Presumptive and Confirmatory Drug TestsCraig AndersonTests for illegal drugs were performed on unknowns obtained from over-the-counter cold medicines. Substances that tested positive for the qualitative Marquis color test were found to be false positives for illegal substances, while scopolamine hydrochloride shows a false positive for cocaine hydrochloride with the cobalt thiocyanate reagent. Anderson, Craig. J. Chem. Educ.2005, 82, 1809.

Drugs / Pharmaceuticals |

Qualitative Analysis |

Acids / Bases |

Gas Chromatography |

IR Spectroscopy |

Mass Spectrometry

Using "Basic Principles" To Understand Complex Science: Nicotine Smoke Chemistry and Literature AnalogiesJeffrey I. SeemanThe HendersonHasselbalch equation calculates the equilibrium distribution of 50:50 for nicotine in its nonprotonated (free base form), relative to its monoprotonated form, at pH of 8 in dilute aqueous solution. This ratio has then been used in the literature to predict the effect of ammonia compounds in tobacco and in smoke on nicotine pyrolysis and smoke chemistry. Experiments demonstrate that neither the thermal chemistry of tobacco alkaloids nor the transfer of nicotine from tobacco to smoke can be explained by the position of the nonprotonated versus monoprotonated form equilibrium in aqueous extracts of tobacco. The high thermal stability of nicotine in air allows nicotine salts to be converted to nonprotonated nicotine and volatilize during heating prior to any substantial decomposition of the nicotine moiety. In contrast, cocaine hydrochloride is thermally unstable and will rapidly decompose upon heating; cocaine hydrochloride must first be converted to its nonprotonated form prior to heating and volatilization. Seeman, Jeffrey I. J. Chem. Educ.2005, 82, 1577.

Acids / Bases |

Applications of Chemistry |

Calorimetry / Thermochemistry |

Heterocycles |

pH |

Natural Products |

Gases

Application of ChemDraw NMR Tool: Correlation of Program-Generated 13C Chemical Shifts and pKa Values of para-Substituted Benzoic AcidsHongyi WangAn application of ChemDraw NMR Tool was demonstrated by correlation of program-generated 13C NMR chemical shifts and pKa values of para-substituted benzoic acids. Experimental 13C NMR chemical shifts were analyzed in the same way for comparison. The project can be used as an assignment at the end of the first-year organic chemistry course to review topics or explore new techniques: Hammett equation, acidbase equilibrium theory, electronic nature of functional groups, inductive and resonance effects, structurereactivity relationship, NMR spectroscopy, literature search, database search, and ChemDraw software.Wang, Hongyi. J. Chem. Educ.2005, 82, 1340.

Demonstrating Encapsulation and Release: A New Take on Alginate Complexation and the Nylon Rope TrickAndrienne C. Friedli and Inge R. SchlagerThree variations on a classroom demonstration of the encapsulation of droplets and evidence for release of the interior solution are described. The first two demonstrations mimic biocompatible applications of encapsulation. A third encapsulation exercise exploits the irreversible interfacial polymerization of diamine and diacid chloride to form membranes and illustrates the detection of diamine release from the capsule using an indicator. Friedli, Andrienne C.; Schlager, Inge R. J. Chem. Educ.2005, 82, 1017.

Biotechnology |

Acids / Bases |

Applications of Chemistry |

Carbohydrates |

Consumer Chemistry |

Membranes

Equilibrium Constants and Water ActivityDavid KeeportsGeneral chemistry instructors are faced with a dilemma when introducing the topic of equilibrium constants: These constants are correctly written in terms of activities, yet activity is a complex topic better treated rigorously in a physical chemistry course than superficially in a general chemistry course. Thus, to introduce equilibrium calculations, it is necessary to use approximate forms for equilibrium constants. However, I find that some commonly used textbooks provide incorrect arguments leading to approximate equilibrium constants for aqueous reactions.Keeports, David. J. Chem. Educ.2005, 82, 999.

Acids / Bases |

Aqueous Solution Chemistry |

Equilibrium |

Water / Water Chemistry

Reaction to "Chemistry Is Not a Laboratory Science"Lawrence J. SacksStephen Hawkes has stirred us to reconsider whether, in fact, chemistry is a laboratory science by positing that lab work does not enhance students understanding of chemistrys centrality, but makes chemistry an irrelevance. This sweeping generalization of what some (maybe even most) labs do is further confounded by a fallacious premise; hence, the major thrust of the proposition likely will beand well should beviewed with utmost skepticism.Sacks, Lawrence J. J. Chem. Educ.2005, 82, 997.

Laboratory Computing / Interfacing |

Learning Theories |

Lewis Acids / Bases |

Nonmajor Courses |

Theoretical Chemistry |

Student-Centered Learning

Reaction to "Chemistry Is Not a Laboratory Science"Lawrence J. SacksIn response to Stephen Hawkes Commentary, I think the crucial point is whether the students learn to appreciate the intellectual beauty of science and understand the relatively small number of simple yet profound scientific principles which govern so much of our everyday experiences. Many non-science majors are obviously disinterested in the laboratory work in introductory courses.Sacks, Lawrence J. J. Chem. Educ.2005, 82, 997.

Laboratory Computing / Interfacing |

Student-Centered Learning |

Learning Theories |

Lewis Acids / Bases |

Nonmajor Courses |

Theoretical Chemistry

Formation of α-Tetralone by Intramolecular Friedel–Crafts AcylationMichael S. Holden, R. David Crouch, and Kathryn A. BarkerA microscale procedure is described for the formation of the industrially-important compound alpha-tetralone. This is an example of an intramolecular FriedelCrafts acylation, utilizing 4-phenylbutanoic acid and a proton source. The title reaction demonstrates the concept of ring-forming reactions and highlights the use of carboxylic acids as an electrophile precursor in electrophilic aromatic substitution reactions. Holden, Michael S.; Crouch, R. David; Barker, Kathryn A. J. Chem. Educ.2005, 82, 934.

Aromatic Compounds |

Microscale Lab |

Synthesis |

Carboxylic Acids |

IR Spectroscopy |

NMR Spectroscopy

On Teaching Ionic Activity Effects: What, When, and Where?Robert de LevieIonic activity effects modify many quantitative chemical relationships involving ions, including those describing equilibria, pH measurements, titrations, diffusional mass transport, and reaction rates. Some of the resulting activity corrections are reviewed, and it is argued that their subtlety requires that they be introduced late rather than early in the chemistry curriculum and then are treated in more detail than is now customary. It is illustrated that interionic effects often cannot be taken into account by merely replacing all ionic concentrations by the corresponding ionic activities. de Levie, Robert. J. Chem. Educ.2005, 82, 878.

Acids / Bases |

Aqueous Solution Chemistry |

Electrochemistry |

pH |

Thermodynamics |

Titration / Volumetric Analysis

Teaching pH Measurements with a Student-Assembled Combination Quinhydrone ElectrodeFritz Scholz, Tim Steinhardt, Heike Kahlert, Jens R. Pörksen, and Jürgen BehnertA combination pH electrode that can be assembled by the student is described. It consists of a glass holder and two sensors in the form of rubber stoppers that contain quinhydrone and graphite. The combination electrode is suitable to teach potentiometric measurements, pH measurements, and the interplay of acidbase and redox equilibria. The electrode meets highest safety standards and overcomes the troubles associated with the use of the conventional quinhydrone electrode.Scholz, Fritz; Steinhardt, Tim; Kahlert, Heike; Pörksen, Jens R.; Behnert, Jürgen. J. Chem. Educ.2005, 82, 782.

A Quantitative Examination of Multiple Methods for Standardizing a Dilute Hydrochloric Acid Solution in an Undergraduate Chemistry LaboratoryNancy E. Meagher, Dana B. Bowens, and B. Shawn ClarkThe objective of the project was to compare the different published methods for standardizing dilute hydrochloric acid solutions. There are three different suitable bases available for the process and multiple indicator choices. This article attempts to identify the most accurate method(s) for use in the undergraduate laboratory. Students were given an "unknown" solution of dilute HCl and assigned to standardize it by eight methods (32 titrations), reporting both their experimental results and preference for the different indicatorbase combinations.Meagher, Nancy E.; Bowens, Dana B.; Clark, B. Shawn. J. Chem. Educ.2005, 82, 428.

Acids / Bases |

Quantitative Analysis

Analysis of Natural Buffer Systems and the Impact of Acid Rain. An Environmental Project for First-Year Chemistry StudentsDavid C. Powers, Andrew T. Higgs, Matt L. Obley, Phyllis A. Leber, Kenneth R. Hess, and Claude H. YoderThe purpose of this project is to investigate the basic principles involved in acidbase buffer systems within the context of an environmental issue. It is designed for use in an introductory chemistry course. The students will learn about acidbase interactions and examine how a buffer system composed of a weak acid and its conjugate base can neutralize large quantities of strong acid while resisting drastic change in the pH of the system. Students will also analyze experimentally the various components of the most commonly occurring natural buffer system.Powers, David C.; Higgs, Andrew T.; Obley, Matt L.; Leber, Phyllis A.; Hess, Kenneth R.; Yoder, Claude H. J. Chem. Educ.2005, 82, 274.

Acids / Bases |

Aqueous Solution Chemistry |

Equilibrium

Analysis of Gold Ores by Fire AssayKristy M. Blyth, David N. Phillips, and Wilhelm van BronswijkThis article describes a laboratory exercise for the analysis of gold using the fire-assay technique. This method of analysis not only provides students with an introduction to the technique of fire assay, but also covers some very interesting acidbase and redox chemistry. The gold is collected in a lead button while the remainder of the constituents find their way into a slag. The gold is recovered from the lead by absorption in a boneash cupel. Blyth, Kristy M.; Phillips, David N.; van Bronswijk, Wilhelm. J. Chem. Educ.2004, 81, 1780.

Acids / Bases |

Industrial Chemistry |

Metals |

Quantitative Analysis |

Oxidation / Reduction

Use of a Tea Infuser To Submerge Low-Density Dry IceCarl P. FictorieA tea infuser is used as a container to hold low-density dry ice. When used with the classic demonstration where dry ice is used to acidify a solution in a graduated cylinder, the dry ice is suspended in the middle of the cylinder, allowing the solution in the upper half of the cylinder to change color while the lower half remains unchanged. Phase changes, acidbase chemistry, and diffusion phenomena are all illustrated. Fictorie, Carl P. J. Chem. Educ.2004, 81, 1473.

Acids / Bases |

Aqueous Solution Chemistry |

Laboratory Equipment / Apparatus |

Phases / Phase Transitions / Diagrams

Unified Approximations: A New Approach for Monoprotic Weak Acid–Base EquilibriaHarry L. Pardue, Ihab N. Odeh, and Teweldemedhin M. TesfaiThis article describes a new approach to approximate calculations for monoprotic acidbase equilibria in otherwise pure water. The new approach, identified herein as unified approximations, uses a simple decision criterion to select between situations that should be treated as deprotonation and protonation reactions. The remaining treatment takes account of changes in concentrations of conjugate acidbase pairs for all situations and ignores autoprotolysis only for situations for which the analytical concentration of either the conjugate acid or conjugate base will always be larger than zero. Pardue, Harry L.; Odeh, Ihab N.; Tesfai, Teweldemedhin M. J. Chem. Educ.2004, 81, 1367.

Acids / Bases |

Equilibrium |

Chemometrics

The Conversion of Carboxylic Acids to Ketones: A Repeated DiscoveryJohn W. Nicholson and Alan WilsonThis article describes the history of the reaction converting carboxylic acids to ketones. The reaction has been rediscovered several times, yet has actually been known for centuries. Nicholson, John W.; Wilson, Alan. J. Chem. Educ.2004, 81, 1362.

Synthesis |

Carboxylic Acids |

Aldehydes / Ketones

Sulfuric Acid and Water: Paradoxes of DilutionI. A. LeensonThe principal goal of this article is to elucidate some uncommon phenomena that can be observed in the process of diluting sulfuric acid with water.Leenson, I. A. J. Chem. Educ.2004, 81, 991.

Lewis Acid–Base, Molecular Modeling, and Isotopic Labeling in a Sophomore Inorganic Chemistry LaboratoryChip Nataro, Michelle A. Ferguson, Katherine M. Bocage, Brian J. Hess, Vincent J. Ross, and Daniel T. SwarrComputational methods can be introduced to simulate IR spectra and to view the HOMO of the Lewis base and the LUMO of the Lewis acid. In addition to the computational exercise, NaBD4 can be used in the synthesis of the adduct in place of NaBH4. This allows the students to observe the effect of isotopic labeling on IR spectra. Nataro, Chip; Ferguson, Michelle A.; Bocage, Katherine M.; Hess, Brian J.; Ross, Vincent J.; Swarr, Daniel T. J. Chem. Educ.2004, 81, 722.

Lewis Acids / Bases |

Molecular Modeling |

Isotopes |

IR Spectroscopy |

Laboratory Computing / Interfacing

Keynotes in Organic Chemistry (Andrew F. Parsons)Joel M. KartyAs a result of the trend towards modularization of chemistry courses, the text attempts to meet the need for smaller, highly focused and accessible organic chemistry textbooks, which complement the very detailed standard texts, to guide students through the key principles of the subject.Karty, Joel M. J. Chem. Educ.2004, 81, 651.

An Acid Hydrocarbon: A Chemical ParadoxJeffrey T. BurkeThis article explores the use of paradox as a teaching and learning strategy. Specifically, students observe the acid-like paradoxical behavior of the hydrocarbon cyclopentadiene. This observation then serves as a springboard to an understanding of the non-benzenoid aromatics. Burke, Jeffrey T. J. Chem. Educ.2004, 81, 65.

Simple Experiments To Demonstrate Proton Flux in Pseudomonas after Alkaline or Acidic StressGabriela Previtali, Walter Giordano, and Carlos E. DomenechA laboratory experiment to ascertain the bacterial response to the stress produced by suspension in different pH solutions has been developed. This laboratory experiment has the pedagogical advantage of giving chemistry students experience with the application of various pH levels to a biological system and enables the students to expand their understanding of pH to mean more than a strictly chemical concept. Previtali, Gabriela; Giordano, Walter; Domenech, Carlos E. J. Chem. Educ.2003, 80, 1468.

The pH at the First Equivalence Point in the Titration of a Diprotic AcidAddison AultI read with interest the paper entitled Easy Derivation of pH  (pKa1 + pKa2)/2 Using Autoprotolysis of HA: Doubtful Value of the Supposedly More Rigorous Equation. I believe the validity of this simple result can be seen even more easily than this paper indicates. Ault, Addison. J. Chem. Educ.2003, 80, 1382.

Acids / Bases |

Equilibrium |

pH |

Titration / Volumetric Analysis

An Aquatic Chemistry Spreadsheet for General Chemistry ClassesChulsung KimThe Aquatic Chemistry Spreadsheet was produced to help students work through the activities of producing a graph of a titration curve, a distribution diagram, and buffer intensity as a function of pH. These activities help students better understand acidbase equilibrium by exploring the relationship between pKa/pKb, pH, ionization fractions, and buffer intensity.Kim, Chulsung. J. Chem. Educ.2003, 80, 1351.

Acids / Bases |

Aqueous Solution Chemistry |

Water / Water Chemistry

Using Hydrocarbon Acidities To Demonstrate Principles of Organic Structure and BondingAndrew P. DicksThis article demonstrates the utility of hydrocarbon acidity as a teaching tool within the undergraduate classroom. Acidities of compounds containing only hydrogen and carbon vary by at least 50 orders of magnitude. Differences in acidities are rationalized by invoking principles of hybridization, resonance, induction, and aromaticity. Dicks, Andrew P. J. Chem. Educ.2003, 80, 1322.

Teaching Introductory Organic Chemistry: 'Blooming' beyond a Simple TaxonomyMichael D. Pungente and Rodney A. BadgerApplying Bloom's taxonomy to introductory organic chemistry classes in order to help students construct their own understanding of the material rather than simply memorize it; includes examples of questions at the various cognitive levels.Pungente, Michael D.; Badger, Rodney A. J. Chem. Educ.2003, 80, 779.

Acids / Bases |

Learning Theories

Organic Functional Group Playing Card DeckMichael J. WelshOrganic functional group playing card deck used for review of the name and structure of organic functional groups that can be used to play any game that a normal deck of cards is used for.Welsh, Michael J. J. Chem. Educ.2003, 80, 426.

The Relative Acidities of Water and MethanolHenry I. AbrashAnalysis of the disparity between the way the acidity constant of water is presented in general chemistry and organic chemistry textbooks.Abrash, Henry I. J. Chem. Educ.2001, 78, 1496.

Evaluating Solubility of Sparingly Soluble Diprotic Acid SaltsJean M. NigrettoThe use of logarithmic concentration diagrams as a convenient tool for finding approximate solutions to the pH of solutions containing sparingly soluble diprotic acid salts in pure water; an application of this method based on a series of carbonate salts is presented.Nigretto, Jean M. J. Chem. Educ.2001, 78, 631.

The Strength of the Hydrohalic AcidsRoland Schmid and Arzu M. MiahThis article brings to mind that the textbook acidity constants of the hydrohalic acids (except for HF) are erroneous because of outmoded conjectures about the HX solubilities. Here we invoke theoretical calculations of HX solubilities based on current solvation models. Schmid, Roland; Miah, Arzu M. J. Chem. Educ.2001, 78, 116.

Comparisons and Demonstrations of Scientific CalculatorsMyung-Hoon Kim, Suw-Young Ly, and Tae-Kee HongScientific calculators are compared in terms of their capacities, featuring many advantages of the graphic calculator over simple nongraphic calculators. Applications in this paper include a simulation of acid-base titration curves, and graphic display of a time course of concentrations of reactants and products for a chemical reaction with first-order kinetics.Kim, Myung-Hoon; Ly, Suw-Young; Hong, Tae-Kee. J. Chem. Educ.2000, 77, 1367.

When A + B B + AErling Antony, Lindsay Mitchell, and Lauren NettenstromMany acid-base chemistry demonstrations and laboratory manuals include the "baking soda volcano". Others use the formation of calcium carbonate from calcium hydroxide and carbon dioxide in human breath. This demonstration uses principles from both as well as stoichiometry to answer the question "Does the order of mixing of reagents make a difference?" Antony, Erling; Mitchell, Lindsay; Nettenstrom, Lauren. J. Chem. Educ.2000, 77, 1180.

Acids / Bases |

Stoichiometry |

Reactions

Every Year Begins a MillenniumJerry A. BellThis article outlines a series of demonstrations and their contexts, leading to recommendations about what we teach and how we teach.Bell, Jerry A. J. Chem. Educ.2000, 77, 1098.

Acids / Bases |

Aqueous Solution Chemistry |

Equilibrium |

Kinetics |

Learning Theories

Two Faces of AlkaloidsJirí DostálThe article discusses and compares the salts and free bases of six well-known alkaloids: nicotine, morphine, cocaine, sanguinarine, allocryptopine, and magnoflorine. Relevance for the biological and medical uses of these compounds is emphasized. Dostál, Jirí. J. Chem. Educ.2000, 77, 993.

Elucidation of Molecular Structure Using NMR Long-Range Coupling: Determination of the Single Isomer Formed in a Regiospecific ReactionSamuel Delagrange and Françoise NepveuThe experiment presented in this article introduces students to the main concepts of two essential NMR techniques for investigating molecular structure. Heteronuclear multiple bond connectivity (HMBC) and proton-coupled 13C NMR are used to determine which isomer, from a possible two, is formed by a regiospecific reaction. The demonstration, based on long-range coupling between quaternary carbons and protons on neighboring carbons, is presented step by step. Delagrange, Samuel; Nepveu, Françoise. J. Chem. Educ.2000, 77, 895.

A Simple Laboratory-Constructed Automatic TitratorKurt L. Headrick, Terry K. Davies, and Aaron N. HaegeleThe construction of a simple automatic titrator is described. The buret is replaced with a metering pump to provide a constant flow of titrant. The output from the pH meter is sent to a recorder via a laboratory- constructed differentiator, allowing the results to be plotted as potential versus time, first or second derivativeHeadrick, Kurt L.; Davies, Terry K.; Haegele, Aaron N. J. Chem. Educ.2000, 77, 389.

Synthesis of Derivatives of (1R)-(-)- and (1S)-(+)-10-Camphorsulfonic AcidSteven C. Cermak and David F. WiemerThe preparation of optically active (camphorsulfonyl)oxaziridines from commercially available (1R)-(-) and/or (1S)-(+)10-camphorsulfonic acid provides a clear demonstration of the lack of relationship between absolute configuration and optical rotation. The parent sulfonic acid can be converted to the corresponding acid chloride and then to the sulfonamide, sulfonylimine, and finally to an oxaziridine in a series of practical organic laboratory experiments.Cermak, Steven C.; Wiemer, David F. J. Chem. Educ.1999, 76, 1715.

Stereochemistry |

Synthesis |

Aromatic Compounds |

Ethers |

Alcohols |

Aldehydes / Ketones |

Acids / Bases

Environmental Chemistry Using UltrasoundBelinda K. Wilmer, Edward Poziomek, and Grazyna E. OrzechowskaIn this demonstration, we describe a simple method for presenting the usefulness of sonication in environmental chemistry. When an aqueous solution of carbon tetrachloride is sonicated, it degrades to produce HCl and HOCl. These products cause a reduction of pH, which can be observed visually with a pH indicator. Wilmer, Belinda K.; Poziomek, Edward; Orzechowska, Grazyna E. J. Chem. Educ.1999, 76, 1657.

Acids / Bases |

Aqueous Solution Chemistry |

pH

Antacids Revisited with Modern Chemical Instruments: GCMS, AAS, and CCTStanley L. Burden and Christopher J. PetzoldThis paper describes a novel experiment that requires students to obtain and interpret data from several analytical techniques to identify the brand name of a commercial antacid. They are required to design a set of experiments utilizing computer controlled titrations (CCT), atomic absorption (AA), gas chromatography-mass spectroscopy (GCMS), and careful quantitative manual titrations using a visual indicator of their choice to determine the brand name of their sample from a list of six to eight choices. Burden, Stanley L.; Petzold, Christopher J. J. Chem. Educ.1999, 76, 1544.

The Softening of Hard Water and Complexometric Titrations: An Undergraduate ExperimentHelena Ceretti, Enrique A. Hughes, and Anita ZaltsAn experiment in which (i) water hardness is explained and demonstrated; (ii) ion-exchange resin properties are visually demonstrated and then used for softening water; (iii) complexometric titrations are used for evaluating water hardness before and after softening; and (iv) acid-base titration can be used to show that the Ca/Mg ions removed by the ion exchanger are replaced by H ions. Ceretti, Helena; Hughes, Enrique A.; Zalts, Anita. J. Chem. Educ.1999, 76, 1420.

Ion Exchange |

Quantitative Analysis |

Titration / Volumetric Analysis |

Water / Water Chemistry |

Acids / Bases

Thermochromism in Commercial ProductsMary Anne White and Monique LeBlancMany commercial products change color with a change of temperature. How do they do it? The processes responsible for the two major categories of commercial thermochromic coloring agents are presented, along with a description of applications of thermochromic materials. White, Mary Anne; LeBlanc, Monique. J. Chem. Educ.1999, 76, 1201.

Acids / Bases |

Consumer Chemistry |

Materials Science |

Applications of Chemistry

Spreadsheet Techniques for Evaluating the Solubility of Sparingly Soluble Salts of Weak AcidsJosé L. Guinón, José García-Antón, and Valentín Pérez-HerranzA spreadsheet of Microsoft Excel for determining the solubility of sparingly soluble salts is described. The chart and worksheet are shown simultaneously on the screen. The worksheet can be used for any salt by merely changing the data for the solubility product constant and ionization constants.Guinn, Jos L.; Garca-Antn, Jos; Prez-Herranz, Valentn. J. Chem. Educ.1999, 76, 1157.

A New Concept for pH-Potential CalculationsK. L. ChengThis paper discusses the concept of pH-potential calculations and indicates that the pH electrode is a capacitor, not a half-cell as currently believed. Cheng, K. L. J. Chem. Educ.1999, 76, 1029.

Instrumental Methods |

Acids / Bases |

Electrochemistry |

Quantitative Analysis |

Electrolytic / Galvanic Cells / Potentials |

pH

A General Simulator for Acid-Base TitrationsRobert de LevieGeneral formal expressions are provided to facilitate the automatic computer calculation of acid-base titration curves of arbitrary mixtures of acids, bases, and salts, without and with activity corrections based on the Davies equation. de Levie, Robert. J. Chem. Educ.1999, 76, 987.

Acids / Bases |

Quantitative Analysis |

Titration / Volumetric Analysis

Predicting Acid-Base Titration Curves without CalculationsDennis W. BarnumIn this paper a qualitative and systematic method for sketching titration curves is presented. Even the more complex cases such as salts or polyprotic acids and bases are treated just as easily as simple monoprotic acids. Having students predict the shape of titration curves from known equilibrium constants helps to focus attention on the general principles without distraction by the mathematics. Barnum, Dennis W. J. Chem. Educ.1999, 76, 938.

Acids / Bases |

Quantitative Analysis |

Water / Water Chemistry |

Equilibrium |

Learning Theories |

Titration / Volumetric Analysis |

Chemometrics

Do pH in Your HeadAddison AultEvery aqueous solution has a pH. Two factors determine this pH: the acidic or basic strength of the solute, and its concentration. When you use pKa values to express acidic and basic strength you can easily estimate the approximate pH of many aqueous solutions of acids, bases, and their salts and their buffers.Ault, Addison. J. Chem. Educ.1999, 76, 936.

Equilibrium |

Acids / Bases |

Aqueous Solution Chemistry |

Learning Theories |

Chemometrics |

Brønsted-Lowry Acids / Bases

Why Not Replace pH and pOH by Just One Real Acidity Grade, AG?Henk van LubeckThe disadvantages of pH and pOH disappear after replacing them with AG, the acidity grade: AG = log [H+]/[OH-]. AG of neutral solutions equals 0 at all temperatures, whereas AG of acidic solutions is positive and of alkaline solutions, negative. AG offers some other minor advantages as well. van Lubeck, Henk. J. Chem. Educ.1999, 76, 892.

Acids / Bases |

Aqueous Solution Chemistry |

Equilibrium

A Simple and Convenient Method for Generation and NMR Observation of Stable CarbanionsHamid S. KasmaiA simple and convenient method for the generation and NMR study of stable carbanions is described. The data and sample spectra illustrate that reliable and good quality NMR spectra of stable carbanions may be obtained. The experiments described provide a good opportunity for students to apply the basic principles of 1H and 13C NMR spectrometry and the interesting topic of the exchange phenomenon in NMR.Kasmai, Hamid S. J. Chem. Educ.1999, 76, 830.

Acids / Bases |

Reactive Intermediates |

NMR Spectroscopy |

Aromatic Compounds

Preparation and Identification of Benzoic Acids and Benzamides: An Organic "Unknown" LabDouglass F. Taber, Jade D. Nelson, and John P. NorthropThe reaction of an unknown substituted benzene derivative with oxalyl chloride and aluminum chloride gives the acid chloride. Hydrolysis of the acid chloride gives the acid, and reaction of the acid with concentrated aqueous ammonia gives the benzamide. The equivalent weight of the acid can be determined by titration; given this information and the melting points of the acid and the benzamide, it is possible to deduce the structure of the initial unknown. Taber, Douglass F.; Nelson, Jade D.; Northrop, John P. J. Chem. Educ.1999, 76, 828.

Qualitative Analysis |

Aromatic Compounds |

Carboxylic Acids

Redox Buffer StrengthRobert de LevieThe proper functioning of enzymes in bodily fluids requires that the pH be maintained within rather narrow limits. The first line of defense against large pH fluctuations in such fluids is the passive control provided by the presence of pH buffers. It is equally important for many enzymes that the redox potential is kept within a narrow range. In that case, stability of the potential is most readily achieved with a redox buffer. In this communication the redox buffer strength is defined by analogy with acid-base buffer strength.de Levie, Robert. J. Chem. Educ.1999, 76, 574.

The Ammonia Smoke Fountain: An Interesting Thermodynamic AdventureM. Dale AlexanderThe ammonia smoke fountain demonstration utilizes a modification of the apparatus used in the standard ammonia fountain. The modification allows for the introduction of hydrogen chloride gas into a flask of ammonia rather than water. The flow rate of hydrogen chloride gas into the flask in the smoke fountain is not constant, but periodic; that is, the smoke puffs from the end of the tube. This unexpected behavior elicits an interesting thermodynamic explanation.Alexander, M. Dale. J. Chem. Educ.1999, 76, 210.

Acids / Bases |

Gases |

Thermodynamics |

Reactions |

Stoichiometry |

Precipitation / Solubility

Is It Real Gold?Harold H. HarrisThe oxidation-reduction couples involved in the corrosion of gold alloys and the dissolution of "noble" metals are related to an inquiry to the newspaper columnist, Ann Landers. the origin of several contemporary phrases (touch stone, acid test, Hallmark) are found in the chemistry of gold. Harris, Harold H. J. Chem. Educ.1999, 76, 198.

Acids / Bases |

Oxidation / Reduction |

Qualitative Analysis |

Applications of Chemistry

A Unified Titration FormulaP. GlaisterIn a number of standard titrations, a volume of a monoprotic base MOH at a specific concentration is added to a volume of a monoprotic acid HA at a specific concentrations. Four different types of titration are possible, depending on whether the acid and base are strong or weak. A single unifying formula covering all four cases has been determined. Glaister, P. J. Chem. Educ.1999, 76, 132.

Acids / Bases |

Titration / Volumetric Analysis |

Quantitative Analysis

Buffers PlusRichard W. RametteIn 1989 JCE Software published The Acid-Base Package: A Collection of Useful Programs for Proton Transfer Systems. This DOS program has been fully upgraded by the same author to the world of Windows 95. Ramette, Richard W. J. Chem. Educ.1998, 75, 1504.

Acids / Bases

Using Bad Science To Teach Good ChemistryMichael S. EpsteinThis paper presents examples of bad science ranging from "unintentional mistakes" to "fraud" that can be used as part of traditional courses in general and analytical chemistry to encourage scientific reasoning and ethical behavior, and to provide a classroom atmosphere that encourages students to think and learn. Epstein, Michael S. J. Chem. Educ.1998, 75, 1399.

Acids / Bases

A Modified Synthesis of the Insect Repellent DEETPeter H. Knoess and Edward G. NeelandIn the preparation of the insect repellent DEET, lab procedures prepare the intermediate m-toluoyl chloride by heating m-toluic acid with thionyl chloride for times ranging from 15 to 45 minutes. The acid chloride is then worked up under Schotten-Baumann conditions to yield DEET.Knoess, Peter H.; Neeland, Edward G. J. Chem. Educ.1998, 75, 1267.

Synthesis |

Aromatic Compounds |

Carboxylic Acids

Kinetic Demonstration of Intermolecular General Acid (GA) Catalysis in Thiolysis of 9-Anilinoacridine Mohammad Niyaz KhanAfter nearly five decades of active research and numerous publications on GA-GB catalysis, introduction of an experiment on GA for students majoring in enzymology/physical organic chemistry at advanced undergraduate/postgraduate level is appropriate. A kinetic experiment involving the reaction of 2-mercaptoethanol (2-ME) with 9-anilinoacridine (9-ANA) is designed to demonstrate intermolecular GA catalysis. Khan, Mohammad Niyaz. J. Chem. Educ.1998, 75, 632.

Bioinorganic Chemistry |

Bioorganic Chemistry |

Mechanisms of Reactions |

Catalysis |

Acids / Bases |

Kinetics

Determination of the Equilibrium Constants of a Weak Acid: An Experiment for Analytical or Physical Chemistry Russell A. BonhamAllows students to explore the concepts of chemical equilibria, nonideal behavior of aqueous solutions, least squares with adjustment of nonlinear model parameters, and errors. The relationship between the pH of a solution of known initial concentration and volume of a weak acid as it is titrated by known volumes of a monohydroxy strong base is developed rigorously assuming ideal behavior.Bonham, Russell A. J. Chem. Educ.1998, 75, 631.

Acids / Bases |

Equilibrium |

Aqueous Solution Chemistry |

Titration / Volumetric Analysis

Letters to the EditorThe author points out that in a previous article, "Why Is Bismuth Subchloride Soluble in Acid," a key reaction which aids in the dissolving of bismuth subchloride is omitted.J. Chem. Educ.1998, 75, 523.

Acids / Bases |

Equilibrium |

Precipitation / Solubility

Mechanism Templates: Lecture Aids for Effective Presentation of Mechanism in Introductory Organic ChemistryBrian J. McNelisTo promote active student learning of mechanism in introductory organic chemistry, hand-outs have been developed with incomplete structures for reaction processes depicted, which are called mechanism templates. The key to these lecture aids is to provide only enough detail in the diagram to facilitate notetaking, ensuring that these templates are dynamic learning tools that must be utilized by an engaged and alert student.Brian J. McNelis. J. Chem. Educ.1998, 75, 479.

Organic Chemistry (by Maitland Jones, Jr. )Michael S. HoldenThe general framework that Jones uses is that of Lewis acids reacting with Lewis bases, with an emphasis on the interaction of filled and empty orbitals. Again and again, as you work your way through the text, there are examples of reactions being explained by the overlap of orbitals. Holden, Michael S. J. Chem. Educ.1998, 75, 291.

A Study of the pH of Sweat for Horses: A Student-Devised Study by Science and Health Science MajorsJohn Tierney, Lori Peacock, Erica Sorkin, and Susan WareThis article describes the results obtained when the pH for horse sweat was measured. Comparisons with the studies on humans are also noted. The pH of perspiration produced by mares and gelding was measured under controlled conditions and found to be between 6.7 to 10. Tierney, John; Peacock, Lori; Sorkin, Erica; Ware, Susan. J. Chem. Educ.1997, 74, 1135.

Learning Theories |

Acids / Bases |

Drugs / Pharmaceuticals |

Undergraduate Research

Buffer Index and Buffer Capacity for a Simple Buffer SolutionVeronica Chiriac, Gabriel BaleaMany papers that present the buffering effect of the simple buffer solution consider the notion of buffer index and buffer capacity as being equivalent. Moreover, IUPAC defies them as the same thing. According to the definition of the authors who have introduced these two units, the paper shows that there is a large difference between them.Chiriac, Veronica ; Balea, Gabriel. J. Chem. Educ.1997, 74, 937.

Sheldon Shore, Small Boranes, and AmmoniaRobert W. ParryThe paper discusses the early studies on "the diammoniate of diborane" and emphasizes how continuing work done by Sheldon Shore at Ohio State University extended the work on the boranes and answered here-to-fore vexing structural problems on intermediates in the borane and borane-ammonia system.Parry, Robert W. J. Chem. Educ.1997, 74, 512.

Acids / Bases |

Coordination Compounds |

Crystals / Crystallography |

Synthesis

The Chemistry of Paper Preservation: Part 4. Alkaline PaperHenry A. CarterThe use of alkaline paper can minimize the problem of acidity for new papers. This study focuses on the chemistry involved in the sizing of both acid and alkaline papers and the types of fillers used. The advantages and potential problems in alkaline paper making are also discussed. Carter, Henry A. J. Chem. Educ.1997, 74, 508.

Acids / Bases |

Industrial Chemistry |

Applications of Chemistry

Why is Bismuth Subchloride Soluble in Acid?Damon DiementeIt is shown that the solubility of BiOCl can be explained as a consequence of the shifting of hydrolysis equilibriums upon the addition of acid. Two demonstrations suitable for classroom use are presented, with detailed discussion of each.Diemente, Damon. J. Chem. Educ.1997, 74, 398.

Acids / Bases |

Equilibrium |

Precipitation / Solubility |

Solutions / Solvents

Virtual Titrator: A Student-Oriented InstrumentDavid Ritter and Michael JohnsonA virtual autotitrator based on an Orion pH meter, a 386 CPU computer, and a homemade stepper-motor driven syringe, and a stopped-flow spectrometer interfaced to a 386 CPU computer which uses a virtual oscilloscope program written in Visual Basic to collect and display the data. Ritter, David; Johnson, Michael. J. Chem. Educ.1997, 74, 120.

Titration / Volumetric Analysis |

Acids / Bases |

Equilibrium |

pH |

Laboratory Equipment / Apparatus |

Laboratory Computing / Interfacing

Reduction of Carboxylic Acids with Sodium Borohydride and an ElectrophileJan William Simek, Thad Tuck, and Kelly Courter BushIntegration of new reduction conditions into a procedure applicable to the first-year organic chemistry laboratory, where reduction of the carboxylic acid group has remained an obstacle, notwithstanding the use of borane or LiAlH4 (2) on the microscale. The NaBH4 method with either electrophile can be modified to any scale; in our hands, the use of I2 as the electrophile performed better at the semimicro scale than the H2SO4 method. Simek, Jan William; Tuck, Thad; Bush, Kelly Courter . J. Chem. Educ.1997, 74, 107.

Carboxylic Acids |

Aromatic Compounds |

Oxidation / Reduction

An Organoleptic Laboratory ExperimentJohn M. RisleyCompounds in ten different classes of organic molecules that are used in the fragrance and food industry are provided to students. Students whiff the vapors of each compound and describe the organoleptic properties using a set of terms utilized in the fragrance and food industry. A set of questions guides students to an understanding of the relationship between structure of molecules and smell.Risley, John M. J. Chem. Educ.1996, 73, 1181.

Molecular Properties / Structure |

Consumer Chemistry |

Physical Properties |

Nonmajor Courses |

Alcohols |

Aldehydes / Ketones |

Amines / Ammonium Compounds |

Carboxylic Acids |

Esters |

Ethers |

Phenols

Optical Basicity: A Practical Acid-Base Theory for Oxides and OxyanionsJ. A. DuffyThe optical basicity concept relies on the Lewis approach to acids and bases and was developed for dealing with chemical problems in non-aqueous, non-protonic media such as silicates, phosphates and borates which are important in glass making and (as slags) for refining steel.Duffy, J. A. J. Chem. Educ.1996, 73, 1138.

Acids / Bases |

Lewis Acids / Bases

Determination of the Dissociation Constant for Monoprotic Acid by Simple pH MeasurementsR. García-Doménech, J. V. de Julián-Ortiz, G. M. Antón-Fos, and J. Galvez AlvarezThe dissociation constant for a weak monoprotic acid may be calculated in aqueous alkaline solution by straightforward pH measurements, before and after the addition of the acid, and with the advantage of not having to standardize the solutions. García-Doménech, R.; de Julián-Ortiz, J. V.; Antón-Fos, G. M.; Alvarez, J. Galvez. J. Chem. Educ.1996, 73, 792.

A Simpler Approach to "Apparent" pKa'sKildahl, NicholasAddition to a recent article on pH, indicating an approach which emphasizes the chemistry behind the titration of a weak acid.Kildahl, Nicholas J. Chem. Educ.1996, 73, 598.

All Positive Ions Give Acid Solutions in WaterStephen J. HawkesThe acidity of aqueous solutions of positive ions is never zero although many texts say incorrectly that most metals of Groups I and II and some others are not acidic.Hawkes, Stephen J. J. Chem. Educ.1996, 73, 516.

Acids / Bases |

Metals |

Solutions / Solvents |

pH

The Teaching of Precipitation Equilibrium: A New ApproachAna M. V. S. V. CavaleiroIn this paper we present a simplified integrated approach to the calculation of the solubility in water of a salt, and the pH of the saturated solution, taking into account the acid-base reactions of the anion. Cavaleiro, Ana M. V. S. V. J. Chem. Educ.1996, 73, 423.

Not So Late Night Chemistry with USDKoppang, Miles D.; Webb, Karl M.; Srinivasan, Rekha R.Through the program, college students enhance their knowledge and expertise on a chemical topic and gain experience in scientific presentations. They also serve as role models to the high school students who can relate to college students more easily than the chemistry faculty members and their high school students.Koppang, Miles D.; Webb, Karl M.; Srinivasan, Rekha R. J. Chem. Educ.1994, 71, 929.

Forensic Chemistry |

Polymerization |

Electrochemistry |

Isotopes |

Acids / Bases

Teaching the Truth about pHHawkes, Stephen J.-log[H+] is only an approximation to pH; how to teach pH to avoid misleading students.Hawkes, Stephen J. J. Chem. Educ.1994, 71, 747.

pH |

Acids / Bases |

Aqueous Solution Chemistry |

Equilibrium

Fruit Anthocyanins: Colorful Sensors of Molecular MilieuCurtright, Robert D.; Rynearson, James A .; Markwell, JohnProvides background and references as a starting point for the further exploration of anthocyanins.Curtright, Robert D.; Rynearson, James A .; Markwell, John J. Chem. Educ.1994, 71, 682.

TITRATE: A Learning Tool for Acid-Base TitrationsRamette, Richard W.Software that calculates and simulates the plot of a titration curve for any base or acid (up to hexaprotic) or any mixture (up to five substances).Ramette, Richard W. J. Chem. Educ.1994, 71, 238.

Potentiometric measurements in a freshwater aquariumHarris, Thomas M.The author describes a laboratory activity for an instrumental methods course that is both interesting and instructive to the students while providing a lesson in environmental chemistry and tropical fish care.Harris, Thomas M. J. Chem. Educ.1993, 70, 340.

Acids / Bases |

Applications of Chemistry |

Green Chemistry |

Quantitative Analysis |

Instrumental Methods

The Erosion of Carbonate Stone by Acid Rain: Laboratory and Field InvestigationsBaedecker, Philip A.; Reddy, Michael M.Describes a laboratory experiment on the effects of acidic deposition on carbonate stone erosion. The purpose is to answer questions concerning the effects of hydrogen ion deposition on stone erosion processes that are difficult to resolve in field experiments alone.Baedecker, Philip A.; Reddy, Michael M. J. Chem. Educ.1993, 70, 104.

The acid equilibrium constant is unity!Baldwin, W. G.; Burchill, C. E.The attempt to assign a non-unity value to this equilibrium constant is a consequence of misunderstanding the way in which the (nearly) constant concentration or activity of the solvent in a dilute solution (or of a pure solid or liquid in a heterogeneous system) is treated when formulating the conventional equilibrium constant expression.Baldwin, W. G.; Burchill, C. E. J. Chem. Educ.1992, 69, 514.

Acidities of oxoacids: Correlation with charge distributionMeek, Terry L.In an attempt to ascertain whether acidity can be correlated with some molecular parameter, the charge distribution within 24 oxoacid molecules and their conjugate base anions were examined by calculating the partial positive or negative charge on each atom.Meek, Terry L. J. Chem. Educ.1992, 69, 270.

The pH of any mixture of monoprotic acids and basesHerman, D. P.; Booth, K. K.; Parker, O. J.; Breneman, G. L.115. Bits and pieces, 44. The pH of any mixture of monoprotic weak and strong acids and bases can be calculated. A curve can also be plotted for the titration of the mixture by any monoportic weak or strong acid or base.Herman, D. P.; Booth, K. K.; Parker, O. J.; Breneman, G. L. J. Chem. Educ.1990, 67, 501.

Acids / Bases |

Titration / Volumetric Analysis |

pH

The Ka values of water and the hydronium ion for comparison with other acidsCampbell, Mark L.; Waite, Boyd A.A primary interest in establishing the correct Ka values for water and the hydronium ion is to be able to compare the strengths of these species acting as acids with the strengths of other compounds acting as acids.Campbell, Mark L.; Waite, Boyd A. J. Chem. Educ.1990, 67, 386.

The perils of carbonic acid and equilibrium constantsJencks, William P.; Altura, Rachel A.It is important to remember that the small amounts of carbon dioxide that are usually present in water can have large effects on acid-base equilibria of dilute solutions and that dilute solutions of most weak acids and bases undergo significant protonation or hydrolysis when they are dissolved in water.Jencks, William P.; Altura, Rachel A. J. Chem. Educ.1988, 65, 770.

Advances in acid-base Gran plot methodologySchwartz, Lowell M.By suitable modifications in the data analysis, Gran plot methodology can be extended to acidic or basic analyte solutions that would be difficult to treat by the conventional equations.Schwartz, Lowell M. J. Chem. Educ.1987, 64, 947.

Acids / Bases |

Titration / Volumetric Analysis

Buffer capacity: An undergraduate laboratory experimentRusso, Steven O.; Hanania, George I. H.A quantitative experiment that can demonstrate buffer action and the measurement of buffer capacity, for a given buffer system, over a range of pH.Russo, Steven O.; Hanania, George I. H. J. Chem. Educ.1987, 64, 817.

Acids / Bases |

pH |

Aqueous Solution Chemistry

Recent advances in the concept of hard and soft acids and basesPearson, Ralph G.The hard / soft acids / bases principle has been justifiably criticized because of the lack of a precise definition of hardness and the inability to quantify this property; recent developments have overcome these objections, however.Pearson, Ralph G. J. Chem. Educ.1987, 64, 561.

How soft is mercury?Rustad, Douglas S.The conclusion that the softness of the Hg(II) ion varies going from the gas phase to different solvents is incorrect.Rustad, Douglas S. J. Chem. Educ.1987, 64, 470.

Buffer demonstrationOphardt, Charles E.Emphasizes the difference in properties between strong and weak acids and that only a weak acid or base and its salt are a buffer.Ophardt, Charles E. J. Chem. Educ.1985, 62, 608.

A short set of 13C-NMR correlation tablesBrown, D. W.The object of these tables is to enable a student to calculate rapidly approximate d values for 13C nuclei in as wide a variety of compounds as possible.Brown, D. W. J. Chem. Educ.1985, 62, 209.

Cooking with chemistryGrosser, Arthur E.Two demonstrations involving cooking eggs and suggestions for many more examples of cooking that illustrate important principles of chemistry. From the "State-of-the-Art Symposium for Chemical Educators: Chemistry of the Food Cycle".Grosser, Arthur E. J. Chem. Educ.1984, 61, 362.

"To sink or swim"O'Connor, RodA problem regarding the maximum water hardness that can be permitted in a swimming pool if it is desired to avoid calcite formation given the carbonate ion concentration. [Debut]O'Connor, Rod J. Chem. Educ.1980, 57, 151.

Buffer effect demonstration on the overhead projectorHobe, Paul G., Jr.Illustrates that one drop of dilute acid or base will change the pH of water by a large amount while larger amounts can be added to a buffer solution before any change is noted.Hobe, Paul G., Jr. J. Chem. Educ.1979, 56, 47.

Favorskii rearrangement in bridged polycyclic compoundsChenier, Philip J.Favorskii rearrangement in bridged polycyclic compounds: This can be classified as an intramolecular rearrangement from carbon to carbon, involving a migrating group Z moving without its electrons from migrating origin A to an electron-rich terminus B.Chenier, Philip J. J. Chem. Educ.1978, 55, 286.

Mechanisms of Reactions |

Carboxylic Acids |

Aldehydes / Ketones |

Aromatic Compounds

Unified calculation of titration curvesStairs, Robert A.A method of calculation is presented that the author hopes will supplement the traditional methods based on appropriate approximations.Stairs, Robert A. J. Chem. Educ.1978, 55, 99.

Collision and transition state theory approaches to acid-base catalysisDunford, H. B.Shows that the description of acid-catalyzed chemical reactions in terms of transition state acid dissociation constants is formally equivalent to the collision theory approach, in which dissociation constants of acid groups on initial reactants are utilized.Dunford, H. B. J. Chem. Educ.1975, 52, 578.

Extraction of acid with aqueous baseSilversmith, Ernest F.This is a visual demonstration of the principle that acidic organic substances can be extracted from an organic solvent via conversion to a salt, and the latter extracted from the aqueous solution via reconversion to the acid form.Silversmith, Ernest F. J. Chem. Educ.1972, 49, A694.

Safe handling of the perchloric acid in the laboratoryMuse, Lowell A.Following a perchloric acid explosion at the University of Georgia, a practical set of recommendations for the safe handling and storage of perchloric acid was developed.Muse, Lowell A. J. Chem. Educ.1972, 49, A463.

Polybasic weak acids indistinguishable from monobasic ones by acid-base titrimetryMeites, LouisPresents a general equation describing the statistical ratio of the ith an (i + 1)th dissociation constants of a j-basic acid and shows that any such acid whose dissociation constants conform to those ratios will give a titration curve indistinguishable from that obtained for a monobasic acid at an appropriate concentration.Meites, Louis J. Chem. Educ.1972, 49, 682.

Acid and base catalyzed isomerization of 5-cholesten-3-one. An experiment in UV/kineticsDimmel, Donald R.; McKinney, Michael A.This experiment is designed to introduce the student to the principles of ultraviolet spectroscopy and point out its application to following the rate of a chemical change; the experiment also clearly demonstrates that a conjugated system is thermodynamically more stable than a nonconjugated system.Dimmel, Donald R.; McKinney, Michael A. J. Chem. Educ.1972, 49, 373.

Identification of an unknown ester: An analytical-organic experimentGrob, Robert L.; Husk, G. RonaldIt is the student's challenge to hydrolyze an ester, separate and purify the resultant alcohol and acid, determine several physical and chemical characteristics, and arrive at a logical choice for its identity.Grob, Robert L.; Husk, G. Ronald J. Chem. Educ.1969, 46, 769.

Computer programs for calculating pHSchlessinger, Gert G.A brief note on the availability of a Fortran II program for calculating the pH of weak acids and bases and salts of these species in aqueous solution.Schlessinger, Gert G. J. Chem. Educ.1969, 46, 680.

Chromic acid oxidation of alcohols: A simple experiment on reaction ratesLanes, Rose M.; Lee, Donald G.In this experiment, students determine the relative rates of oxidation by adding quantities of several different alcohols to a solution of chromium(VI) in dilute sulfuric acid and visually monitoring the course of the reaction.Lanes, Rose M.; Lee, Donald G. J. Chem. Educ.1968, 45, 269.

Dissociation of weak acids and bases at infinite dilutionStock, D. IrwinIt is all too easy to forget that in a solution of infinite dilution the solvent itself is ionized to an extent governed by its ionization constant, and that the concentration of its ions will appear in the expression for the dissociation constant of the solute.Stock, D. Irwin J. Chem. Educ.1967, 44, 764.

Theoretical error in acid-base titrationsButcher, John; Quintus, FernanadoThe purpose of this report is to describe simple derivations of equations for titration error calculations for a number of acid-base titrations, and to show error curves for some typical cases.Butcher, John; Quintus, Fernanado J. Chem. Educ.1966, 43, 546.

Effect of amine structure on the relative acidity of conjugate acidsGriswold, Robert E.the primary objectives of this experiment are to investigate the effect of structure of amines on the relative acidity of their conjugate acids and to study some of the factors affecting equilibrium constants.Griswold, Robert E. J. Chem. Educ.1965, 42, 483.

Acids / Bases |

Molecular Properties / Structure |

Amines / Ammonium Compounds |

Equilibrium |

pH

Applications of sodium-lead alloy in qualitative inorganic analysisEdge, Robert A.; Fowles, Gerald W. A.This note describes how sodium-lead alloy may be used n qualitative inorganic analysis, both as a reductant in acid and alkaline media, and as a source of sodium hydroxide for hydroxide precipitations.Edge, Robert A.; Fowles, Gerald W. A. J. Chem. Educ.1965, 42, 436.

Lineweaver-Burk treatment of acid-base dissociationSolomons, C. C.The advantage of using the Lineweaver-Burk treatment of acid-base dissociation before introducing the Henderson-Hasselbalch equation lies in the fact that K (dissociation) is determined by a straight-line relationship which is nonlogarithmic.Solomons, C. C. J. Chem. Educ.1965, 42, 225.

Teaching ionic equilibrium: Use of log chart transparenciesFreiser, Henry; Fernando, QuintusThe use of graphical methods brings the problem of significance of various terms in complicated expressions into proper focus. Furthermore, a pictorial representation permits the student to see at a glance how the concentrations of various species in a system at equilibrium change with conditions.Freiser, Henry; Fernando, Quintus J. Chem. Educ.1965, 42, 35.

Development of the pH concept: A historical surveySzabadvary, Ferenc; Oesper, Ralph E., trans.Traces the historical development of the following: a recognition of the importance of hydrogen ion concentration; an understanding of buffer solutions; and the concept and measurement of pH.Szabadvary, Ferenc; Oesper, Ralph E., trans. J. Chem. Educ.1964, 41, 105.

The hydrated hydronium ionClever, H. LawrenceIt is the purpose of this brief review to cite and discuss some of the evidence for the existence of the trihydrated hydronium ion.Clever, H. Lawrence J. Chem. Educ.1963, 40, 637.

The decarboxylation of organic acidMarch, JerrySimple aliphatic acids (except for acetic) do not give good yields of the corresponding alkanes through decarboxylation, although many organic chemistry textbooks cite this as a general method for the preparation of alkanes.March, Jerry J. Chem. Educ.1963, 40, 212.

Acids / Bases |

Reactions |

Synthesis |

Alkanes / Cycloalkanes |

Carboxylic Acids

Graphical treatment simplifies acid-base equilibria calculationsThomas, E. B.In dealing with equilibria involving polybasic acids, considerable simplification of the calculation of the relative distribution of the various species with changes in pH may be obtained by a graphical treatment of the ratios involved.Thomas, E. B. J. Chem. Educ.1963, 40, 70.

Acids / Bases |

Equilibrium |

Chemometrics |

pH

Calculating titration errorsButler, James N.This paper presents some explicit expressions for the titration error in acid-base and precipitation titrations, as well as a simple method for deciding qualitatively whether or not a given titration is feasible.Butler, James N. J. Chem. Educ.1963, 40, 66.

Easily prepared wide range buffer seriesCarmody, Walter R.A series of buffers with pH values ranging from 2.0 to 12.0 that requires the preparation of only two stock solutions and requires only three common chemicals.Carmody, Walter R. J. Chem. Educ.1961, 38, 559.

An approach to complex equilibrium problemsButler, James N.Presents an approach to equilibrium problems that sets up enough equations relating the various concentrations present to define the system completely and then makes approximations that simplify the equations.Butler, James N. J. Chem. Educ.1961, 38, 141.

A separation and identification experiment for elementary organic chemistry laboratoryLaughton, Paul M.The student selects a test tube containing two unknowns and is told only that they have been selected from two of three possible groups: a primary or tertiary amine, an aldehyde or ketone, and an acid or phenol. The components are to be separated, their physical properties determined, their categories assigned, and one specific derivative prepared for each.Laughton, Paul M. J. Chem. Educ.1960, 37, 133.

Amphoteric molecules, ions and saltsDavidson, DavidIt is the aim of this paper to call attention to the splendid opportunity amphoteric substances afford for the teaching of acid-base principles.Davidson, David J. Chem. Educ.1955, 32, 550.

Molecular Properties / Structure |

Acids / Bases |

pH |

Aqueous Solution Chemistry

A mnemonic for dicarboxylic acidsCox, Gerald J.This short note provides a mnemonic for the names of the dicarboxylic acids.Cox, Gerald J. J. Chem. Educ.1955, 32, 363.

Two experiments in spectrophotometryPhillips, John P.Presents procedures for determining the ionization constants of weak acids and a complex formula by the method of continuous variations through spectrophotometry.Phillips, John P. J. Chem. Educ.1954, 31, 81.

Spectroscopy |

Acids / Bases |

Aqueous Solution Chemistry |

Coordination Compounds

Investigation of complex metal ions by the polarographic methodGayer, Karl H.; Demmler, Anita; Elkind, Michael J.The purpose of this paper is to present in a simplified and readily understandable manner the outline of one of the instrumental methods that, in recent years, has become an increasingly prominent tool in the investigation of complex metal ions.Gayer, Karl H.; Demmler, Anita; Elkind, Michael J. J. Chem. Educ.1953, 30, 557.

Coordination Compounds |

Instrumental Methods |

Electrochemistry |

Oxidation / Reduction |

Acids / Bases |

Aqueous Solution Chemistry

LettersDavidson, DavidResponds to comments made in a related letter.Davidson, David J. Chem. Educ.1953, 30, 534.

Equilibrium |

Chemometrics |

Acids / Bases |

Aqueous Solution Chemistry |

Oxidation / Reduction

LettersRicci, John E.Discusses the question of teaching students how to "solve" problems requiring more than one equilibrium constant.Ricci, John E. J. Chem. Educ.1953, 30, 532.

Acid-base titration curves: An experiment in acidimetryHendel, James M.The purpose of this activity is to introduce a bit of research into the quantitative analysis course and to illustrate the value of titration curves in deciding what indicator should be used for a particular acid-base titration.Hendel, James M. J. Chem. Educ.1952, 29, 148.

Acids / Bases |

Titration / Volumetric Analysis |

Aqueous Solution Chemistry |

Quantitative Analysis

A common misunderstanding of Hess' lawDavis, Thomas. W.The statement, sometimes attributed to Hess, that "In any series of chemical or physical changes the total heat effect is independent of the path by which the system goes from its initial to its final state" is incorrect.Davis, Thomas. W. J. Chem. Educ.1951, 28, 584.

Stoichiometry |

Acids / Bases |

Aqueous Solution Chemistry |

Calorimetry / Thermochemistry

Teaching amino acid formulationPatton, A. R.Presents a device that aids in explaining the concept of dipolar ions necessary to an understanding of the behavior of amino acids and proteins.Patton, A. R. J. Chem. Educ.1951, 28, 471.

An experiment for the pH meterPecsok, Robert L.These procedures are designed for a Beckman Model H-2 line operated pH meter and include standardization, measurement of pH, titration curve of phosphoric acid, standardization of base, and analysis of mixed phosphate solutions.Pecsok, Robert L. J. Chem. Educ.1951, 28, 252.